High efficiency semi-articulated railway power bogie

ABSTRACT

An improved semi-articulated railway power bogie has a pair of multiple axle sub-bogies semi-articulated for creep force turning control while retaining freedom of rocking and relative longitudinal motion. An equalized centered bolster suspension and low load transfer rod linkage maintain high equalization of loads and tractive forces at the wheels to provide overall high adhesion and curving efficiency. Various improvements may include a preloaded resilient compression element in an articulating mechanism for improved sub-bogie turning control, two piece bearing adapters carrying primary spring suspensions and with rubber bushed traction rods and lateral thrust control for transmitting longitudinal and lateral forces to sub-bogie frames, and rubber bushed nose links connecting traction motor nose connections to transoms of the frames.

TECHNICAL FIELD

This application claims priority from U.S. Provisional Patent Application No. 60/547,007 filed Feb. 12, 2004.

TECHNICAL FIELD

This invention relates to railway power trucks, or bogies, and in particular to high efficiency semi-articulated railway power bogies having improved features.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,485,743 discloses an eight wheel, four axle semi-articulated railway locomotive power truck. The truck includes dual two axle sub-truck frames connected by a span bolster and semi-articulated for steering control.

The delivery of tractive effort from the sub-truck frames is through a low mounted traction rod linkage. The truck also features centered support of the bolster between the axles of each sub-truck frame and the retention of freedom for vertical and longitudinal motion between the semi-articulated truck frame ends while maintaining the desired lateral interconnection for steering control.

SUMMARY OF THE INVENTION

The present invention provides an improved high efficiency semi-articulated railway power bogie of the general type described in the previously mentioned U.S. Pat. No. 4,485,743.

The new bogie provides advantages such as improved distribution of locomotive weight to the rails and reduced wheel and rail wear resulting from steering interaction between front and rear power sub-bogies, as well as other features which are inherent in articulated power bogie arrangements. In addition, certain components of the assembly have been modified or replaced by improved designs or mechanisms that improve control, reduce wear, increase operational life or improve serviceability, thus reducing the cost of utilizing bogies of this type in railway operation.

The semi-articulating lateral tie rod of the previous design is provided with pre-compressed resilient (rubber) bushings in place of spherical bearings. The bushings eliminate clearance and provide controlled stiffness of the lateral end frame connection that increases steering stability and reduces hunting of the connected sub-bogies.

The pedestals and journal boxes of the previous design are replaced by bearing adapters, which may house sealed axle bearing assemblies carried on the ends of the wheel set axles. The bearing adapters support primary suspension coil spring members with body roll motions controlled by dampers connected between the adapters and the bogie frames. Longitudinal traction and braking forces are carried by traction rods connected between the bearing adapters and the frames, with rubber bushings at connecting joints to provide preloaded frictionless connections. The bushings are preloaded to provide clearance-free guidance, which improves stability at higher speeds.

Bonded rubber thrust pads on the bearing adapters engage plastic (such as nylon) wear plates on the bogie side frames and control lateral thrust forces from the wheel assemblies. The combination provides improved ride control and life with wear-free traction rod bushings.

Two-piece bearing adapters are provided which allow wheel/axle assemblies to be easily replaced by removing lower bearing retainers without requiring separation of the adapter upper bearing housings and other connected components. Replacement of the wheel and axle assemblies is simplified by this feature.

Traction motor support includes a nose link with preloaded rubber bushings. The nose link replaces a nose pack assembly that includes wearing parts with a wear-free assembly.

These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary side view of a railway locomotive having a semi-articulated four axle railway power bogie in accordance with the invention;

FIG. 2 is a plan view of the railway bogie as seen from the plane indicated by the line 2-2 of FIG. 1;

FIG. 3 is a bottom view of the railway bogie of FIGS. 1 and 2;

FIG. 4 is a fragmentary cross-sectional view from the plane of the line 4-4 of FIG. 3 showing a resilient bushing joint connection of an articulating transverse link to a sub-bogie frame;

FIG. 5 is an enlarged fragmentary side view of an end-axle bearing adapter with traction rod connection to a sub-bogie frame;

FIG. 6 is a cross-sectional view of the bearing adapter application from the plane of the line 6-6 of FIG. 5;

FIG. 7 is a cross-sectional view of a traction rod joint from the plane of the line 7-7 of FIG. 5; and

FIG. 8 is a cross-sectional view of traction motor support link applications from the plane of the line 8-8 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in detail, numeral 10 generally indicates a portion of one end of a railway locomotive having a carbody 11 supported, in an exemplary embodiment, by a four axle semi-articulated railway bogie shown in FIGS. 1-3 and generally indicated by numeral 12.

Railway bogie 12 includes a span bolster 14 that is pivotably connected at its center to the carbody by a center plate 15. From the center plate the bolster extends longitudinally forward and rearward approximately one-quarter the total length of the bogie to transversely extending support legs 16, 18.

The bolster is supported in a manner to be subsequently described by first and second interconnected sub-bogies 20, 22 having separate frames 23, 24 respectively. Each of the frames comprises a pair of generally linear side rails 26 connected together by laterally extending center transoms 27. The side frames are also connected across the adjacent ends of the associated bogies by end transoms 28, 30, respectively, which are interconnected in a manner to be subsequently described.

Each of the sub-bogies also includes two pairs of rail engaging wheels 31, supporting a pair of rotatable axles 32 carrying on their ends preferably sealed cartridge bearings 34 retained in bearing adapters 35 of the sub-bogie frames. Primary suspension means, such as coil springs 37, are provided between the bearing adapters 35 and slightly raised portions 38 near the ends of the sub-bogie frames for supporting the frames on the wheel and axle assemblies. Secondary suspension means, in the form of resilient pads 39 or other suitable devices, are sandwiched vertically between the ends of the bolster support legs 16, 18 and linear portions 41 of the sub-bogie frames, the suspension pads being longitudinally centered between the axles and equidistant from the bolster center plate.

The primary suspension means permit vertical motion of the individual axle ends relative to the sub-bogie frames within their respective bearing adapters 35 while maintaining substantial equalization of wheel loads. The secondary resilient pad suspensions not only carry vertical loads between the bolster and the sub-bogie frames with resilient cushioning thereof but also permit limited pivoting and lateral motion of the sub-bogie frames with respect to the bolster as will be subsequently more fully described. Placement of the secondary suspension devices equidistant from the bolster center plate and centered between their respective bogie axles provides substantial equalization of vertical loads on the bogie axles.

Each of the sub-bogies also includes a pair of traction motors 42, each geared to drive one of the axles 32 and supported between its respective axle and the adjacent center transom 27 of the respective sub-bogie frame. Brake rigging is provided in the form of frame carried brake cylinders 43 acting through brake levers 44 and links 46 to actuate wheel engaging brake shoes 47 in conventional fashion.

In accordance with the invention, the tractive forces and the dynamic and mechanical braking forces are transmitted from the wheel and axle assemblies to the sub-bogie frames through the axle mounted cartridge bearings 34 and associated bearing adapters 35 by traction rods 48 to be subsequently more fully described. These forces are then transmitted from each of the sub-bogie frames to the locomotive carbody by means of a low level horizontal transfer rod linkage system connected with a pair of stanchions 49 that extend downwardly from opposite sides of the locomotive carbody to locations laterally opposite the longitudinal center of the bogie 12 and the associated center plate 15. If desired, the stanchions may, alternatively, be formed as extensions of the bolster 14 with the tractive and braking forces being transmitted to the carbody through the center plate 15.

Separate linkages from each sub-bogie include longitudinal transfer rods 50 that extend horizontally along the sides of the bogie toward the front and rear from the bottoms of the stanchions 49, at a level preferably as low as possible and generally about ten inches above the rail. The transfer rods 50 connect with laterally projecting arms 51 of transfer levers 52 that are pivotally connected to the side rails of the respective sub-bogie frames near the longitudinal centers thereof. Levers 52 also include generally longitudinal arms 54, thereby forming two bell crank mechanisms that are interconnected by a lateral transfer link 55 which extends through the transverse center transom 27 of its respective sub-bogie to interconnect the longitudinal portions of the transfer linkage extending along the bogie sides.

The transfer linkage not only provides for the transfer of traction and braking loads between the sub-bogie frames and the locomotive carbody through the stanchions but also allows for relative turning and rocking motions of the individual sub-bogie frames with respect to the associated ends of the bolster, which they support. Such turning and rocking motions, generally about the centers of the sub-bogie frames, as well as limited lateral motion with respect to the bolster are permitted by the resilient secondary suspension devices (pads) 39 located between the bolster legs and the sub-bogie frames.

To properly relate steering or turning motions of the sub-bogies 20, 22, in a manner similar to the disclosure of the referenced U.S. Pat. No. 4,485,743, the adjacent ends of the sub-bogie frames 23, 24 are interconnected in semi-articulated fashion to provide interlocking control of the sub-bogie frame turning motions while permitting freedom of the adjacent end portions of the sub-bogie frames for relative vertical and longitudinal motions. In the illustrated embodiment, each end transom 28, 30 is fitted with connections at diagonally opposite locations of the bogie frames. These connections are pivotally connected laterally by a transverse link, such as a tie rod 56. The tie rod positively interconnects the two sub-bogies 20, 22 of the bogie 12 for concurrent lateral motions of their adjacent ends, thus requiring equal and opposite turning motions of the two sub-bogies during curving.

The interconnecting arrangement described provides a construction, referred to herein as semi-articulated, which positively interconnects the two sub-bogie frames to require concurrent lateral motions of their ends. Thus they are interconnected for steering, or relative interrelation of their turning motions to be constrained to equal amounts in opposite directions of rotation or oscillation.

This provides a balancing of creep forces acting on the two sub-bogies during turning, thus giving a steering function between the sub-bogies that reduces wheel flange loads during turning by causing the axles to take a more normal or radial position with respect to the curving rails during a turn than would be the case if the sub-bogies were not laterally interconnected at their ends. At the same time, freedom is provided in the longitudinal and vertical directions for relative motion between the interconnected end transoms of the sub-bogies. This permits them to freely move with respect to one another in the longitudinal and vertical directions so as to avoid interfering with the weight transfer and load equalization characteristics otherwise provided by the bogie 12.

In this regard, the design of the bogie is such as to provide substantially equal distribution of the locomotive weight through the bolster to the separate sub-bogies combined with equal distribution of the weight on each sub-bogie to the axles spaces equidistant from the secondary suspension elements supporting the bolster. This, combined with the low traction linkage system, which efficiently transfers traction forces from the rail to the carbody, provides a very low amount of weight transfer of traction or braking forces from one axle to another.

Thus, there is provided a very high degree of adhesion efficiency for the bogie. The overall result of the low weight transfer characteristics of the bogie and the steering interconnection of the sub-bogies in a manner that does not adversely affect these good weight transfer characteristics is such as to provide a bogie having substantially greater traction efficiency than conventional four, three or even two axle bogies during curve negotiation as well as during operation on tangent or straight track. Curving efficiency is improved and wheel and rail wear are reduced by the steering interconnection of the sub-bogies.

In accordance with the present invention, the features of the transverse link described above are improved by the application of pre-compressed resilient bushings in the pivotal connections between the transverse link, or tie rod 56, and the adjacent end frames 23, 24 of the sub-bogies. In particular, referring to FIGS. 1-4, the tie rod 56 has an eye 58 at both ends, each eye having a cylindrical opening 59 receiving a connecting pin 60 with an annular or tubular rubber bushing 62 compressed between the pin and the opening. The pin 60 includes end flanges 63, which are bolted to bifurcated fingers 64 of a connector 66, provided, one on each bogie frame, on laterally opposite sides of the bogie 12.

The pre-compressed resilient (rubber) bushings 62 provide non-wearing connections without clearance and allowing limited pivoting, but having a controlled stiffness that positively turns the sub-bogies together to provide improved stability in curve negotiation at higher speeds.

Referring to FIGS. 1, 3, 5 and 6, the pedestals and journal boxes of the prior patented truck are replaced in accordance with the invention by the cartridge, or other, bearings 34 received in downwardly open recesses 68 in upper housings 69 of the bearing adapters 35. The adapters include two pieces, including upper housings 69, which receive and transfer vertical, lateral and longitudinal loads from the bearings 34. Separate bearing caps or retainers 70 are secured across open ends of the recesses 68 to maintain the bearings in position. The retainers 70 are removable to facilitate easy removal of wheel and axle assemblies from the bogie for service or replacement. The upper housings 69 and connected components remain in place without requiring disturbance of their fasteners during wheel assembly and bearing service.

The connected components referred to include the primary suspension coil springs 37 which are received in pockets 72 in the slightly raised portions 38 of the frames 23, 24 (see FIGS. 5 and 6). One of telescoping dampers 73, connected vertically between the frames and a bearing adapter 35 for each axle, is also shown. FIG. 6 also illustrates in cross section, one of rubber-bonded thrust pads 74, mounted on upstanding abutments 76 of the adapter upper housings 69 and engagable with suitable wear plates 77, such as nylon or other plastic, mounted inside the frame pockets 72.

FIGS. 1, 3 and 5 best illustrate the traction rods 48 connected longitudinally between the adapter upper housings 69 and depending connecting walls 78 of the sub-bogie frames 23, 24. A cross-sectional view of the attachment to frame 23 is shown in FIG. 7.

Each traction rod 48 has an eye 78 with a cylindrical opening 80 at each end. Within the opening 80 a resilient rubber bushing 81 is compressed between the eye and a steel insert 82. The insert has a slight barrel shape to retain the bushing 81 in place in the eye 78. The insert 82 is secured to the frame 23 by a bolt 84 extending through cooperating openings of the insert and the frame walls 78. A similar connection is provided between the other eye 78 of each traction rod 48 and its associated bearing retainer upper housing 69.

In use, lateral motion of the axles 32 in the frames 23, 24 is constrained by the retainer mounted thrust pads 73 engaging the frame mounted wear plates 76 to resist lateral thrust forces imposed on the wheels and axles during locomotive operation. Longitudinal traction and braking forces are transmitted between the axles 32 and the frames 23, 24 by the traction rods 48. The rubber compression bushings 81 provide preloaded resilient connections without clearance, which assures the same characteristics, with and without traction forces, which do not change over time due to absence of wear in the connections. The preloaded connections of the traction rods provide more stable operation of the bogie at high speeds due to the absence of clearance in the connections.

As a further feature, the bogie 12 also provides an improved traction motor nose suspension, which utilizes the benefits of rubber compression bushings to provide longer service life and improved serviceability to the traction motor mounting. FIG. 8 best illustrates the arrangement which provides a nose link 85 for supporting the nose, or inner side, of each traction motor 42 from the center transom 27 of the associated sub-bogie frame 23, 24. Each nose link has upper and lower support pins 87 received with pre-compressed rubber bushings 88 in eye openings 89 adjacent each end of the link. The pins have flattened ends 90 which are bolted to the transom 27 or to support arms 92 extending from the traction motor noses. The opposite end of each traction motor is conventionally supported by bearings carried on the associated axle.

The nose link suspension replaces a nose pack arrangement which includes wearing components that are eliminated in the new suspension, thereby extending the service life of the nose suspension. Removal of a traction motor is also simplified, since detachment of the nose end requires only unbolting of the pins from the support arms while the motor nose is supported.

While the invention has been described by reference to certain preferred embodiments, it should be understood that numerous changes could be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the disclosed embodiments, but that it have the full scope permitted by the language of the following claims. 

1. In combination in a powered railway bogie: a pair of multiple axle sub-bogies having frames individually supporting and pivotable with respect to a span bolster adapted to support a rail vehicle carbody, said sub-bogies being longitudinally disposed in tandem adjacent end to end relation, said bolster and carbody together constituting supported means carried by said sub-bogies, power means for driving wheels of the bogie, tractive force transfer linkage operatively longitudinally connecting the sub-bogie frames with said supported means, and articulating mechanism laterally positively connecting the adjacent ends of the two sub-bogie frames to correlate pivotal turning motions of the sub-bogies relative to the bolster, said articulating mechanism including a preloaded compression element connected between the sub-bogies and being operative to require substantially equal and opposite simultaneous turning motions of the sub-bogies but providing at least limited freedom of relative vertical and longitudinal motions of the adjacent ends of the sub-bogies with respect to one another, such that coordinated turning control with isolation of inter-frame rocking and traction force effects is provided.
 2. The combination of claim 1 wherein said articulating mechanism comprises a transverse link pivotally connected at opposite corners to the adjacent ends of the two sub-bogie frames.
 3. The combination of claim 2 wherein the compression element is a resilient bushing.
 4. The combination of claim 3 wherein the resilient bushing is rubber.
 5. The combination of claim 1 wherein said sub-bogies each include only four wheels connected with two parallel axles.
 6. The combination of claim 5 including bearings journaling opposite ends of the axles and retained in bearing adapters, resilient support members between the bearing adapters and the sub-bogie frames and operative to absorb vertical support loads, and traction rods connected longitudinally through preloaded resilient bushings between the bearing adapters and the frames of their respective sub-bogies and operative to transmit longitudinal traction and braking forces to and from the bearing adapters.
 7. The combination of claim 6 including lateral thrust pads between the bearing adapters and the bogie frames and operative to absorb lateral thrust forces acting between the frames and the adapters.
 8. The combination of claim 7 wherein the bearing adapters each include an upper bearing housing having a downwardly open ended slot receiving a bearing and a bearing retainer closing the slot and removable for separation of the wheel, axle and bearing assemblies from the bogie frames without disturbing the upper bearing housing connections with the bogie frames
 9. The combination of claim 8 wherein said power means include a traction motor supported between each axle and a cross member of an associated frame, the motor carried at one end by bearings on the associated axle and at an opposite end by a generally vertical nose link between the opposite end and the frame cross member, the link having openings receiving preloaded rubber bushings at each end and operative to support the weight of and absorb shock and vibration loads transmitted to the traction motor.
 10. The combination of claim 1 including bearings journaling opposite ends of the axles and retained in bearing adapters, resilient support members between the bearing adapters and the sub-bogie frames and operative to absorb vertical support loads, and traction rods connected longitudinally through preloaded resilient bushings between the bearing adapters and the frames of their respective sub-bogies and operative to transmit longitudinal traction and braking forces to and from the bearing adapters.
 11. The combination of claim 10 including lateral thrust pads between the bearing adapters and the bogie frames and operative to absorb lateral thrust forces acting between the frames and the adapters.
 12. The combination of claim 11 wherein the bearing adapters each include an upper bearing housing having a downwardly open ended slot receiving a bearing and a bearing retainer closing the slot and removable for separation of the wheel, axle and bearing assemblies from the bogie frames without disturbing the upper bearing housing connections with the bogie frames.
 13. The combination of claim 12 wherein said power means include a traction motor supported between each axle and a cross member of an associated frame, the motor carried at one end by bearings on the associated axle and at an opposite end by a generally vertical nose link between the opposite end and the frame cross member, the link having openings receiving preloaded rubber bushings at each end and operative to support the weight of and absorb shock and vibration loads transmitted to the traction motor.
 14. The combination of claim 13 wherein said articulating mechanism comprises a transverse link pivotally connected at opposite corners to the adjacent ends of the two sub-bogie frames.
 15. The combination of claim 14 wherein the compression element is a resilient bushing. 